pdhpe core 2- body in motion

anatomy

the study of structures of the body and their relationships

the anatomical position

standing upright, facing forward, hands down by side, palms facing forward

sagittal plane

vertical plane that divides the body into left and right

frontal plane

vertical plane that divides the body into front and back

transverse plane

horizontal plane that divides the body into top and bottom

roles of the skeletal system

* **support** - bones provide a framework for the body
* **protection** - bones protect many internal organs from injury
* **movement** - skeletal muscles attach to bones; when muscles pull on bones they produce movement
* **storage of minerals** - bone tissue stores several minerals, particularly calcium and phosphorus
* **blood cell reproduction** - red blood cells, white bloods cells and platelets are formed in bone marrow
* **storage of energy** - a secondary reserve of chemical energy is stored in the bone marrow

bones

* made up of compact bone and spongy bone
* there are four principal types of bone based on shape; long bones, short bones, flat bones, and irregular bones

compact bone

contains few spaces and forms the external layer of all bones

spongy bone

contains marrow, which produces blood cells

long bones

* greater length and width and consist of a shaft; they consist mostly of compact bone encasing spongy bone
* eg. femur, tibia, fibula, phalanges, humerus, radius, ulna

short bones

* somewhat cube-shaped, nearly equal in length and width
* spongy bone except for the surface, which is a thin layer of compact bone
* eg. carpals and tarsals

flat bones

* generally thin and composed of two thin plates of compact bone encasing spongy bone
* eg. cranial bones, sternum, ribs, scapula

irregular bones

* have complex shapes
* vary in the amount of spongy and compact bone
* eg. vertebrae, some facial bones

major bones involved in movement

the adult skeleton consists of 206 bones grouped into two divisions; the axial skeleton and the appendicular skeleton

axial skeleton

* the bones of the axial skeleton lie around the axis
* skull bones, breastbone, ribs, bones of the backbone

appendicular skeleton

* contains the bones of the upper and lower limbs plus the girdles that connect the extremities to the axial skeleton

superior

toward the head

inferior

away from the head

anterior

nearer to the front of the body

posterior

nearer to the back of the body

medial

nearer to the midline of the body

lateral

further from the midline of the body

proximal

nearer to the attachment of an extremity

distal

further from the attachment of an extremity

synovial joints

* freely movable joint
* most joints in the body are synovial joints

articular cartilage

covers the end of the bone providing cushioning and reducing friction during movement

synovial cavity

space that separates the two articulating bones

ligaments

join bone to bone

synovial fluid

acts as a lubricant with the synovial cavity

joint capsule

encloses the cavity and contains the fluid

fibrous capsule

encloses the bones and synovial cavity

synovial membrane

secretes fluid into the joint

meniscus

inward growing cartilage that absorbs shock, pressure, and enhances stability

bursae

saclike structures that are strategically placed to alleviate friction

tendon

join muscle to bone

types of synovial joints

* gliding joint
* hinge joint
* saddle joint
* ellipsoidal/conyloid joint
* ball-and-socket joint
* pivot joint

gliding joint

* side to side
* back and forth
* eg. carpals, tarsals, vertebrae

hinge joint

* the convex surface of one bone fits into the concave surface of another
* movement is in a single direction allowing flexion and extension
* eg. knee, elbow, ankle

saddle joint

* one bone is saddle-shaped while the other bone is shaped like a rider
* side to side
* back and forth
* eg. the thumb

ellipsoidal/condyloid joint

* an oval shaped bone fits into an elliptical cavity of another bone
* side to side
* back and forth
* eg. the joint at the wrist

ball-and-socket joint

* consists of a ball-like surface that fits into a cuplike depression of another
* flexion and extension
* adduction and abduction
* rotation
* eg. the hip and the shoulder
* the shoulder also allows circumuction

pivot joint

* a rounded surface of one bone articulates with a ring formed partly by another
* primary movement is rotation
* eg. the atlas of the neck rotating

flexion

movement as the joint reduces the angle between the bones

extension

movement at the joint increases the angle between the bones

hyperextension and hyperflexion

makes the joint go beyond its normal range of motion

circumduction

the distal end of the body moves in a circle

rotation

the movement of a bone around its axis

abduction

movement of a bone away from the midline of the body

adduction

movement of a bone towards the midline of the body

dorsiflexion

the foot flexes towards the skin

plantarflexion

the foot points down to the ground

supination

movement of the forearm in which the palm is turned anteriorly

pronation

movement of the forearm in which the palm is turned posteriorly

inversion

movement of the sole of the foot inward

eversion

movement of the sole of the foot outward

types of muscle tissue

* skeletal muscle tissue
* cardiac muscle tissue
* smooth muscle tissue

skeletal muscle tissue

* attached primarily to bones
* striated due to its alternating dark and light bands
* a voluntary muscle

cardiac muscle tissue

* forms most of the heart
* striated, but involuntary

smooth muscle tissue

* located in the walls of hollow internal structures, such as the intestines
* smooth in appearance, often involuntary

skeletal muscles

* produce movement by exerting force on tendons, which in turn pull on bones or other structures
* most muscles cross at least one joint and are attached to the articulating bones that form the joint
* normally one bone is held in its original position, while the other bone moves during a contraction
* the attachment of the tendon at the stationary bone is called the origin, while the attachment at a movable bone is the insertion

major muscles of the body

major muscles involved in movement

* most movement requires several muscles working together
* most skeletal muscles are therefore arranged in opposing pairs
* the muscle that causes the desired action is the prime mover or **agonist**
* while the agonist is contracting, its opposing partner is relaxing. the muscle relaxing is known as the **antagonist**
* most movements also include a synergist, which serves to stabilise the movement

types of muscle contraction

there are different types of contractions that muscles are capable of. the muscles will contract according to the need of the movement requires. there are two main types of contractions; isotonic and isometric

isotonic contractions

isotonic contractions occur when the muscle contracts (shortens) and lengthens to produce movement. there are two types of isotonic contractions; concentric contraction and eccentric contraction

concentric contraction

the muscle shortens during the contraction and pulls on another structure to produce movement (eg. flexion phase of bicep curl)

eccentric contraction

the muscle lengthens during the contraction. eccentric contractions result in more delayed onset muscle soreness than concentric contractions (eg. down phase of a push-up)

isometric contractions

occur when the muscle does not or cannot shorten, but the tension on the muscle increases. no movement is produces and the length of the *muscle* stays the same (eg. wall sit)

the respiratory system

the nose

* has an external and internal portion
* the inside of both the external and internal nose is called the nasal cavity. it carries three functions;
* incoming air is warmed, moistened and filtered
* smell stimulus is received
* chambers modify speech sounds

the pharynx

a passageway for both air and food

the larynx

* a short passageway that connects the pharynx to the trachea
* the epiglottis is responsible for directing food and air into the corresponding tubes
* it closes off the larynx ensuring food and liquids go to the oesophagus

trachea

a passageway for air

bronchi

* the trachea divides itself into the left and right bronchus
* these bronchi eventually branch into bronchioles
* this process resembles a tree trunk with its branches, the bronchial tree

lungs

* paired organs within the thoracic activity
* each lung is divided into lobes, which receives the bronchi
* these eventually divide into alveoli, which are tiny air sacs
* the gas exchange takes place within the alveoli

lung function

* the principle purpose of respiration is to supply the cells of the body with oxygen and remove carbon dioxide
* the three processes of this are;
* pulmonary ventilation
* external respiration
* internal respiration

pulmonary ventilation

* more commonly known as breathing
* this is the process by which gases are exchanged between the atmosphere and the human body, mainly the alveoli
* this is due to a pressure gradient

insipration (inhalation)

* for air to flow into the lungs, the size of the lungs needs to increase
* this occurs when the diaphragm and intercostal muscles contract
* this pulls up the ribs upward and sternum forward and consequently the walls of the lungs are pulled outward
* this creates a pressure difference and air enters the lungs

expiration (exhalation)

a passive process due to muscle recoil and surface tension

when the diaphragm and intercostal muscles relax, the ribs move downwards, the lungs decrease in size and the pressure gradient now causes air to exit the lungs

exchange of gases in the lungs

* wherever there is a difference in gases, Boyle’s Law suggests that these gases will move to achieve equilibrium
* the remaining two processes result in the exchange of gases;
* external (pulmonary) respiration
* internal (tissue) respiration

external (pulmonary) respiration

* the exchange of oxygen and carbon dioxide between the alveoli in the lungs and pulmonary blood capillaries
* results in deoxygenated blood becoming oxygenated blood
* deoxygenated blood in the lungs, oxygenated blood in the blood
* the exchange of gases occurs as the carbon dioxide moves into the lungs, while oxygen moves into the blood within the pulmonary cavities

internal (tissue) respiration

* the exchange of oxygen and carbon dioxide between blood capillaries and tissue cells
* results in deoxygenated blood becoming oxygenated blood
* oxygen in blood capillaries, carbon dioxide in tissue cells
* the exchange of gases occurs as the carbon dioxide moves into the blood capillaries, while oxygen moves into the tissue cells throughout the body
* at rest, only about 25% of the oxygen in the blood enters the cells
* the deoxygenated blood returns to the heart, where it begins the cycle again

the circulatory system

includes the cardiovascular system and lymphatic system

cardiovascular aspects

* all cells in the body need;
* oxygen
* nutrients
* waste removed
* main structures involved within the system;
* heart
* blood
* blood vessels

components of blood

* blood is heavier, thicker and more viscous than water
* it makes up approximately 8% of total body weight
* the blood volume of an average-sized;
* male: 5-6 litres
* female: 4-5 litres
* blood has three functions within the body
* transportation
* regulation
* protection
* blood is composed of two portions;
* blood plasma (55%0)
* formed elements (45%)

transportation

* transports oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs
* also carries nutrients, heat, waste products and hormones

regulation

regulates pH levels throughout the body and adjusts body temperature

protection

* clotting protects against blood loss
* antibodies protect agains foreign toxins

blood plasma

* 55%
* a straw-coloured liquid that is mostly water
* also contains waste products, nutrients, vitamins, hormones and enzymes

formed elements

* 45%
* red blood cells (erythocytes)
* white blood cells (leukocytes)
* platelets

red blood cells (erythocytes)

* containing oxygen carrying haemoglobin
* highly specialised in oxygen transport
* live approx. 20 days, 4 m

white blood cells (leukocytes)

responsible for fighting infections within the body

red blood cell : white blood cell ratio

700:1

platelets

help repair damaged blood vessels and promote blood clotting

structure/function of the heart, arteries, veins, capillaries

* the heart is about the size of a closed fist about two-thirds of it lies to the left of the body’s midline within the thoracic cavity
* the heart contains chambers and valves, which fulfil a role in ensuring the effective functioning of the heart, given that it can pump around 7000 litres of blood a day
* blood vessels form a closed system that transports blood to and from the heart

chambers of the heart

* the heart has four chambers;
* the two superior chambers are called the left and right atrium
* the two inferior chambers are called the left and right ventricles

atria

thin walled as they deliver blood to the ventricles

ventricles

* the right ventricle pumps blood to the lungs while the left ventricle pumps blood around the body
* thus, the wall of the left ventricle is 2-4 times as thick as the right ventricle

blood flow within the heart

* the right atrium receives deoxygenated blood from various parts of the body via the superior and inferior vena cava
* from here, the blood travels to the right ventricle where it is pumped via the pulmonary **artery** to the lungs
* the gas exchange occurs within the lungs and the now oxygenated blood travels back via the pulmonary **vein** to the left atrium
* this oxygenated blood then travels to the left ventricle where it is pumped around the body via the aorta

blood vessels

* arteries
* arteries carry blood away from the heart
* arteries have elasticity and contractility. allowing them to be effective in transporting blood around the body
* thick, muscular vessels
* become smaller as they divide and eventually branch into arterioles
* capillaries
* microscopic vessels that connect to arterioles and venules
* found near most cells in the body
* primary function: permit the exchange of nutrients and waste products
* veins
* carry blood to the heart
* their anatomy is very similar to that of an artery. only thinner in some instances
* veins gradually become larger and stem from the smaller vessels, called venules

the pulmonary artery exception

the pulmonary artery carries deoxygenated blood

the pulmonary vein carries oxygenated blood